This invention relates generally to a closed-loop, control system for a stepping motor, and in particular, it relates to such a system and method which enable the stepping motor to operate at high stepping speeds and at varying-torque loads.
In certain business equipment applications, it is necessary to move documents, intermittently, at high feeding rates. For example, in financial business machines, like an encoder or a proofing machine, it is necessary to feed documents, like checks, intermittently, from a stack of documents to a document track in the associated business machine. Because the documents to be processed are generally of varying sizes when received by a bank, these documents present varying-torque loads to a stepping motor which is used to intermittently feed the checks from the stack to the document track or to and away from a reading station which is located along the document track.
Some of the prior art control systems are not adept in maintaining the high stepping rates required for applications similar to the one described in the previous paragraph.